// 你好世界
/* 1、解决TS和JS冲突问题
tsc –-init #生成配置文件
2、自动编译
tsc --watch
3、发出错误
tsc –noEmitOnError 01-te-basic.ts 
4、严格模式
"strict": true,
"noImplicitAny": true, 
"strictNullChecks": true,
*/

/* console.log('Hello World') */
function greet(person,data){
  console.log(`Hello${person},today is ${data}.`)
}
greet('小强qiang',new Date())

/* let msg = 'hello there!'
msg = 'hello world' 
msg = 100 */
let surname:string = undefined
let age:number = null